Suspension of a chess game with the intention to finish it later. It was once very common in high-level competition, often occurring soon after the first time control, but the practice has been abandoned due to the advent of computer analysis. See sealed move.

adjudication

Decision by a strong chess player (the adjudicator) on the outcome of an unfinished game. This practice is now uncommon in over-the-board events, but does happen in online chess when one player refuses to continue after an adjournment.

To adjust the position of a piece on its square without being required to move it. A player may only do this on his turn to move, and he must first say "I adjust", or the French equivalent "J'adoube".

advanced pawn

A pawn that is on the opponent's side of the board (the fifth rank or higher). An advanced pawn may be weak if it is overextended, lacking support and difficult to defend, or strong if it cramps the enemy by limiting mobility. An advanced passed pawn that threatens to promote can be especially strong.

advantage

A better position with the chance of winning the game. Evaluation factors can include space, time, material, and threats.

The standard way to record the moves of a chess game, using alphanumeric coordinates for the squares.

amateur

The distinction between professional and amateur is not very important in chess as amateurs may win prizes, accept appearance fees, and earn any title, including World Champion. In the 19th century, "Amateur" was sometimes used in published game scores to conceal the name of the losing player in a Master vs. Amateur contest. It was thought to be impolite to use a player's name without permission, and the professional did not want to risk losing a customer. See also NN or N.N.

A practice, common in the 19th century, whereby a player would announce a sequence of moves, believed by him to constitute best play by both sides, that led to a forced checkmate for the announcing player in a specified number of moves (for example, "mate in five").

antipositional

A move or a plan that is not in accordance with the principles of positional play. Antipositional is used to describe moves that are part of an incorrect plan rather than a mistake made when trying to follow a correct plan. Antipositional moves are often pawn moves; since pawns cannot move backwards to return to squares they have left, their advance often creates irreparable weaknesses.

Anti-Sicilian

An openingvariation that White uses against the Sicilian Defense (1.e4 c5) other than the most common plan of 2.Nf3 followed by 3.d4 cxd4 4.Nxd4 (the Open Sicilian). Some Anti-Sicilians include the Alapin Variation (2.c3), Moscow Variation (2.Nf3 d6 3.Bb5+), Rossolimo Variation (2.Nf3 Nc6 3.Bb5), Grand Prix Attack (2.Nc3 Nc6 3.f4 g6 4.Nf3 Bg7 and now 5.Bc4 or 5.Bb5), Closed Sicilian (2.Nc3 followed by g3 and Bg2), Smith–Morra Gambit (2.d4 cxd4 3.c3), and Wing Gambit (2.b4).

A game which, under the tournament rules, counts as a win for Black if it ends in a draw. Typically the tournament rules allow White more time than Black in such games: the discrepancy can vary; usually in FIDE World Championships, White has six minutes, while Black only has five, but in the World Chess Championship 2012 the following time control was used: 5 minutes for White, 4 minutes for Black; plus 3 seconds increment per move from move 60. This format is typically used in playoff tie-breakers when shorter blitz games have not resolved the tie.

The sacrifice of minor or major pieces to expose the enemy king. For example, if the black king has castled and is on the g8-square, White may attempt to attract the king by using forcing moves such as Bxh7+, followed by Ng5+ etc. See decoy.

A self-operating chess-playing machine. Popular attractions in the 18th and 19th centuries, these devices were hoaxes under the control of a human player. The most famous chess-playing "automaton" was The Turk.

A checkmate delivered by a rook or queen along a back rank from which the mated king is unable to move because it is blocked by friendly pieces (usually pawns) on the second rank. This is also sometimes referred to as a back-row mate.

back-rank weakness

A situation in which a player is under threat of a back-rank mate and, having no time/option to create an escape for the king, must constantly watch and defend against that threat, for example by keeping a rook on the back rank.

A chess competition in which the players simultaneously play each other two games on two boards; each playing White on one board and Black on the other. There is a clock at both boards. It removes the bonus in mini-matches of playing white first. Basque chess was first played in 2011 in Spain.[1]

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A pair of white rooks are aligned along their battery, ready to do some action.

An arrangement of two pieces in line with the enemy king on a rank, file, or diagonal so that if the middle piece moves a discovered check will be delivered. The term is also used in cases where moving the middle piece will uncover a threat along the opened line other than a check.

A strong grip or stranglehold on a position that is difficult for the opponent to break. A bind is usually an advantage in space created by advanced pawns. The Maróczy Bind is a well-known example. See also squeeze.

A situation in which one player has only his light-square bishop remaining while the other has only his dark-square bishop remaining. In endgames, this often results in a draw if there are no other pieces (only pawns), even if one side has a material advantage of one, two or even three pawns, since the bishops control different squares (see Opposite-colored bishops endgame). In the middlegame, however, the presence of opposite-colored bishops imbalances the game and can lead to mating attacks, since each bishop attacks squares that cannot be covered by the other.

black

The dark-colored squares on the chessboard are often referred to as "the black squares" even though they are often some other dark color. Similarly, "the black pieces" are sometimes actually some other (usually dark) color. See also white.

A fast form of chess (from German Blitz, "lightning") with a very short time limit, usually 3 or 5 minutes per player for the entire game. With the advent of electronic chess clocks, the time remaining is often incremented by 1 or 2 seconds per move.

blockade

A strategic placement of a minor piece directly in front of an enemy pawn, where it restrains the pawn's advance and gains shelter from attack. Blockading pieces are often overprotected.

Boden's Mate, named for Samuel Boden, is a checkmate pattern in which the king, usually having castled queenside, is checkmated by two crisscrossing bishops. Immediately prior to delivering the mate, the winning side typically plays a queen sacrifice on c3 or c6 to set up the mating position.

An opening move found in standard reference books on opening theory. A game is said to be "in book" when both players are playing moves found in the opening references. A game is said to be "out of book" when the players have reached the end of the variations analyzed in the opening books, or if one of the players deviates with a novelty (or a blunder).

A form of chess in which each side has 1 minute to make all their moves.

bust

Colloquial term for a refutation of an opening, or of previously published analysis. A famous example is Bobby Fischer's 1961 article "A Bust to the King's Gambit" in which he wrote, "In my opinion, the King's Gambit is busted. It loses by force."[2]

A tournament round in which a player does not have a game, usually because there are an odd number of players. A bye is normally scored as a win (1 point), although in some tournaments a player is permitted to choose to take a bye (usually in the first or last round) and score it as a draw (½ point).

A tournament organised by the FIDE, the third and last qualifying cycle of the World Chess Championship. The participants are the top players of the Interzonal tournament plus possibly other players selected on the basis of rating or performance in the previous candidates tournament. The top ranking player(s) qualify(ies) for the world championship.

capped piece

A certain piece with which one player tries to deliver checkmate. Agreeing to play with a capped piece provides the stronger player an extra challenge, thereby conferring upon himself a handicap in chess. When the capped piece is a pawn, it is called a pion coiffé [from French: "capped pawn"].

capture

1. [verb] To remove the opponent's man from the board by taking it with one's own man. Except in the case of an en passant capture, the capturing man replaces the captured man on its square.

A special move involving both the king and one rook. Its purpose is generally to protect the king and develop the rook. Castling on the kingside is sometimes called "castling short" and castling on the queenside is called "castling long"; the difference is based on whether the rook moves a short distance (two squares) or a long distance (three squares).

castling into it

A situation where one side castles and a result is that the king is in more danger at the destination than on the initial square, either immediately or because lines and diagonals can be more readily opened against it. Because beginners often falsely assume castling to always improve protection of the king, the pre-war grandmaster and leading figure of the hypermodern schoolRichard Réti exhorted players to "castle because you must, not because you can."

The category of a tournament is a measure of its strength based on the average FIDE rating of the participants. The category is calculated by rounding up the number: (average rating − 2250) / 25. So each category covers a 25-point rating range, starting with Category 1 which spans ratings between 2251 and 2275. A Category 18 tournament has an average rating between 2676 and 2700.

Moving a piece or pieces toward the center of the board. In general, pieces are best placed in or near the center of the board because they control a large number of squares and are available for play on either flank as needed. Because of their limited mobility, knights in particular benefit from being centralized. There are several chess aphorisms referring to this principle: "A knight on the rim is dim [or, grim]" and "A knight on the side cannot abide."

A device made up of two adjacent clocks and buttons, keeping track of the total time each player takes for their moves. Immediately after moving, the player hits his button, which simultaneously stops his clock and starts his opponent's. The picture shown displays an analogue clock where the term flag fall originates. Modern clocks are digital.

1. Removal of pieces from a rank, file or diagonal so that a bishop, rook or queen is free to move along it.

2. Clearing the diagonal : removing pieces from a diagonal so that an enemy bishop, usually a fianchettoed bishop, has no targets to attack.

clock move

In a game played clock move, a move is considered completed only after the clock is pressed. For example, one could touch a piece, then move a different piece—as long as the player has not pressed their clock button. This way of playing is uncommon but can be seen in casual games, rather than in tournaments, which are very likely to use the touch move rule.

Adjective used to describe a move, player, or style of play characterized by risky, positionally dubious play that sets traps for the opponent. The name comes from the notion that one would expect to see such play in skittles games played in a coffeehouse or similar setting, particularly in games played for stakes or blitz chess. The Blackburne Shilling Gambit is a typical example of coffeehouse play.

A clever sequence of moves, often involving a sacrifice, to gain the advantage. The moves of the opponent are usually forced (i.e. a combination does not give the opponent too many possible lines of continuation).

Passed pawns on adjacent files. These are considered to be unusually powerful (often worth a minor piece or rook if on the sixth rank or above and not properly blockaded) because they can advance together. Also see connected pawns.

The improvement of a player's position by the reposition of one or more pieces to better square(s), typically after a player's attack or combination has left his pieces in poor positions or uncoordinated.

This is chess played at a long time control by various forms of long-distance correspondence, usually through a correspondence chess server, through email or by the postal system. Typically, one move is transmitted in every correspondence.

1. A position of key importance in determining the soundness of an openingvariation. In opening preparation, if one side can demonstrate an advantage in a critical position, the other side must either find an improvement or else abandon that variation as inferior.

2. More generally, any position in a game where the next move(s) are apt to determine the outcome (win, draw, or loss).

A cross-check is a check played in reply to a check, especially when the original check is blocked by a piece which itself either delivers check or reveals a discovered check from another piece.

crosstable

An arrangement of the results of every game in a tournament in tabular form. The names of the players run down the left side of the table in numbered rows. The names may be listed in order of results, alphabetically, or in pairing order, but results order is most common. The columns are also numbered, each one corresponding to the player in the same numbered row. Each table cell records the outcome of the game between the players on the intersecting row and column, using 1 for a win, 0 for a loss, and ½ for a draw. (In a double round-robin tournament each cell contains two entries, as each pair of players plays two games alternating White and Black.) Every game is recorded twice, once from the perspective of each player. The diagonal cells that correspond to the player playing himself are marked with a * or × or other symbol since they are not used. For examples see Hastings 1895 chess tournament, Nottingham 1936 chess tournament, and AVRO tournament.

crush

Slang for a quick win, especially an overwhelming attack versus poor defensive play. A crushing move is a decisive one.

The 32 dark-colored squares on the chessboard, such as a1 and h8. A dark square is always located at a player's left hand corner.

dark-square bishop

One of the two bishops that moves on the dark squares, situated on c1 and f8 in the initial position.

dead draw

A drawn position in which neither player has any realistic chance to win. A dead draw may refer to a position in which it is impossible for either player to win (such as insufficient material), or it may refer to a simple, lifeless position which would require a major blunder before either side would have a chance to win.

The inverse of a decoy (see above). Whereas a decoy involves luring an enemy piece to a bad square, a deflection involves luring an enemy piece away from a good square; typically, away from a square on which it defends another piece or threat. Deflection is thus closely related to overloading.

Wouter Mees at a demonstration board

demonstration board

A large standing chess board used to analyse a game or show a game in progress. Johann Löwenthal invented the demonstration board in 1857.

2. A piece to sell itself as dearly as possible in a situation where both sides have hanging pieces.

develop

In the opening, moving a piece from its original square to make it more active. To redevelop a piece means to move it to a better square after it has already been developed. Efficient, effective development of one's pieces is one of the key objectives of the opening phase of the game.

diagonal

A line of squares of the same color touching corner to corner, along which a queen or bishop can move.

A situation whereby capture of a piece is unavoidable despite it having wide freedom of movement. Usually occurs in chess problems. In practical play, an example of domination is a knight on d1 facing an opponent's bishop on d4, other pieces being absent; the bishop covers all of the squares to which the knight may move.

double attack

Two attacks made with one move: these attacks may be made by the same piece (in which case it is a fork); or by different pieces (a situation which may arise via a discovered attack in which the moved piece also makes a threat). The attacks may directly threaten opposing pieces, or may be threats of another kind: for instance, to capture the queen and deliver checkmate.

A check delivered by two pieces at the same time. A double check necessarily involves a discovered check. By its nature a double check cannot be met by interposing a defending piece in the line of attack, or by capturing an attacker; when subjected to a double check, the attacked king must move, which makes the double check especially powerful as an attacking tactic.

A pair of pawns of the same color on the same file; generally considered a weakness due to their inability to defend each other.

doubled rooks

A powerful position in which two of a player's rooks are placed on the same file or rank with no other chessmen between them. In this position, they defend each other while attacking both laterally and along the shared row. The position especially can be decisive when achieved during the endgame phase of play.

A game that ends without victory for either player. Most drawn games are draws by agreement. The other ways that a game can end in a draw are stalemate, threefold repetition, the fifty-move rule, and insufficient material. A position is said to be a draw (or a "drawn position" or "theoretical draw") if either player can, through correct play, eventually force the game into a position where the game must end in a draw, regardless of the moves made by the other player. A draw is usually scored as ½ point, although in some matches only wins are counted and draws are ignored.

draw death

Hypothetical scenario whereby elite-level chess players, aided by modern computer analysis, become so good that they never make mistakes, leading to endless drawn games (since chess is widely believed to be drawn with best play from both sides).

drawing line

An openingvariation that commonly ends in a draw, for example 1.e4 e5 2.Nf3 Nc6 3.Nc3 Nf6 4.Bb5 Nd4 5.Nxd4 exd4 6.e5 dxc3 7.exf6 Qxf6 8.dxc3 Qe5+ 9.Qe2 Qxe2+, a line in the Rubinstein Variation of the Four Knights Game. See Collection of drawing lines.[3] Often such a variation is played because one or both players are eager to draw the game.

A style of play in which the activity of the pieces is favoured over more positional considerations, even to the point of accepting permanent structural or spatial weaknesses. Dynamism stemmed from the teachings of the Hypermodern School and challenged the dogma found in more classical teachings, such as those put forward by Wilhelm Steinitz and Siegbert Tarrasch.

The English Chess Federation (ECF) is the governing chess organisation in England and is one of the federations of the FIDE. It was known as the British Chess Federation (BCF) until 2005 when it was renamed.

The Encyclopaedia of Chess Openings (ECO), a standard and comprehensive chess opening reference. Also a classification system (ECO code) for chess openings that assigns an alphanumeric code from A00 to E99 to each opening.

edge

An edge is a small but meaningful advantage in the position against one's opponent. It is often said White has an edge in the starting position, since he moves first (see First-move advantage in chess).

The Elo rating system is a method for calculating the relative skill levels of chess players, named after the Hungarian Arpad Elo. Since 2012, FIDE publishes a monthly international chess rating list using the Elo system.

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After 1. e4 e6 2. e5 f5, immediately and immediately only after the move 2. ... f5 can white do en passant.

[from French: "in the act of passing"] The rule that allows a pawn that has just advanced two squares to be captured by an enemy pawn that is on the same rank and adjacent file. The pawn can be taken as if it had advanced only one square. Capturing en passant is possible only on the next move.

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The pawn on e4 is en prise.

en prise

[from French: "in a position to be taken",[4][5] often italicized] En prise describes a piece or pawn exposed to a material-winning capture by the opponent. This is either a hanging piece, an undefended pawn, a piece attacked by a less valuable attacker, or a piece or pawn defended insufficiently. For instance, 1.e4 Nf6 2.Nf3? leaves White's e-pawn en prise.

A computerized database of endgames with up to seven pieces, providing perfect play for both players, and thus completely solving those endgames. (Six-piece endgames have been finished; some seven-piece endgames have been finished as of 2008.)

To create a position where the players have equal chances of winning (referred to as: equality). This may be either static equality, where a draw is likely (for example, a balanced endgame), or certain equality (for example, by perpetual check), or dynamic equality, where White and Black have equal chances of winning the game. In opening theory, since White has the advantage of the first move, lines that equalise are relatively good for Black.

1. The capture of a pair of pieces, one white and the other black, usually of the same type (i.e., rook for rook, knight for knight, etc.), or of bishop for knight (two pieces that are considered almost equal in value).

2. The advantage of a rook over a minor piece (knight or bishop). The player who captures a rook for a minor piece is said to have "won the exchange", and the opponent is said to have "lost the exchange". An exchange sacrifice is giving up a rook for a minor piece.

This is a type of opening in which there is an early, voluntary exchange of pawns or pieces.

exhibition

A contest of one or more games played for the purpose of public entertainment, as opposed to a match or tournament. An exhibition may pit two masters against each other, in which case chess clocks are normally used and the contest is quite serious. A simultaneous exhibition/display has one or more masters play many celebrity or amateur opponents at once, and is often not timed.

Refers to an opening tactic of developing a bishop to the board's longest diagonal on the file of the adjacent knight (b2 or g2 for White; b7 or g7 for Black), or the moves to develop a bishop to one of those squares. A fianchetto usually occurs after moving the pawn on that file forward one square (or perhaps two). The Italian word is a noun ("in fianchetto").

The World Chess Federation (Fédération Internationale des Échecs), the primary international chess organizing and governing body. The abbreviated name FIDE is nearly always used in place of the full name in French.

A draw may be claimed if no capture or pawn move has occurred in the last fifty moves by either side.

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The f-file

file

A column of the chessboard. A specific file can be named either using its position in algebraic notation, a–h, or by using its position in descriptive notation. For example, the f-file or the king bishop file comprises the squares f1–f8 (or KB1–KB8 in descriptive notation).

The square upon which a player focuses an attack, for example by repeatedly attacking that square or sacrificing a piece there. For example, in an attack upon an uncastled king, Black's f7-square (or White's f2-square) is a common focal point. Examples of attacks on the focal point f7 include the Fried Liver Attack (initiated by a knight sacrifice on f7) and the primitive Scholar's mate (ending with checkmate on f7).

A sequence of two or more moves culminating in checkmate that the opponent cannot prevent.

forced move

A move that is the only one which does not result in a serious disadvantage for the moving player. Forced can also be used to describe a sequence of moves for which the player has no viable alternative, for example "the forced win of a piece" or "a forced checkmate". In these cases the player cannot avoid the loss of a piece or checkmate, respectively.

forcing move

A move which presents a threat and limits the opponent's responses. Chaining together several forcing moves may result in a combination.

forfeit

Refers to losing the game by absence or by exceeding the time control (forfeit on time).

A simultaneous attack by a single piece on two (or more) of the opponent's pieces (or other direct target, such as a mate threat). When the attacker is a knight the tactic is often specifically called a knight fork. Some sources state that only a knight can give a fork and that the term double attack is correct when another piece is involved, but this is by no means universal usage.

In endgame theory, a fortress is an impenetrable position which, if obtained by the side with a material disadvantage, will result in a draw due to the stronger side's inability to make progress. Some writers have also used the term more loosely to describe a defensive set-up, such as a castled king's position.

friendly game

A game that is not played as part of a match, tournament, or exhibition. Often the game is not timed, but if a chess clock is used rapid time controls are common. The term refers only to the circumstances in which the game is played, not the relationship between the players or the intensity of the competition. Also called a casual game.

The highest title a chess player can attain (besides World Champion). When used precisely, it is the title awarded by FIDE starting in 1950, but it can be used to describe someone of comparable ability. The term International Grandmaster or IGM would refer only to the FIDE title.

A game in which the players quickly agree to a draw after making little or no effort to win. This may be a very boring game, for example 1.d4 d5 2.c4 c6 3.cxd5 cxd5 4.Nc3 Nf6 5.Nf3 Nc6 6.Bf4 Bf5 7.e3 e6 ½–½ (draw agreed), or a superficially exciting game played with a variation the players know leads to a draw, for example 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Bxc6 dxc6 5.0-0 Bg4 6.h3 h5 7.c3 Qd3 8.hxg4 hxg4 9.Nxe5 Bd6 (a pseudo-sacrifice of Black'squeen) 10.Nxd3 Bh2+ 11.Kh1 Bd6+ and Black draws by perpetual check. Although originally used to refer to such games between grandmasters, the term is now used colloquially to refer to any such game.

Two friendly pawns abreast without friendly pawns on adjacent files. Hanging pawns can be either a strength (usually because they can advance) or a weakness (because they cannot be defended by pawns) depending on circumstances.

Harrwitz bishops

A player's light-square and dark-square bishops placed so that they occupy adjacent diagonals; named for the mid-19th century masterDaniel Harrwitz. For example, White has Harrwitz bishops in the Danish Gambit after 1.e4 e5 2.d4 exd4 3.c3 dxc3 4.Bc4 cxb2 5.Bxb2. Harrwitz bishops can be a potent attacking force in the middlegame. Also called raking bishops.

A square that a player does not, and cannot in the future, control with a friendly pawn. The definition is applied conditionally based on the position: the square must have some positional significance to the opponent for it to be considered a hole – squares on the first and second ranks are not holes. An example of a hole is the e4-square in the Stonewall Attack.

a move a human would make, as opposed to the kind of move that only a computer would make.

Hutton pairing

A pairing technique invented in 1921 by George Dickson Hutton for matching teams of players in which only one game is required per player. Has been used regularly for correspondence team events and for matches between many teams conducted on one day. Also called jamboree pairing.

A difference between positions of the white and black pieces. An imbalanced position is one where White and Black both have unique adavntages and chance to win by using those advantages. Conversely, a balanced position is often more drawish.

Refers to the amount of time added to each player's time before each move. For instance, Rapid chess might be played with "25 minutes plus 10 second per move increment", meaning that each player starts with 25 minutes on their clock, and this increments by 10 seconds after (or before) each move, usually using the Fischer Delay method. See Time control#Compensation (delay methods).

A chess opening that begins 1.d4 Nf6. Originally used to describe queen's pawn defences involving the fianchetto of one or both black bishops, it is now used to describe all Black defences after 1.d4 Nf6 that do not transpose into the Queen's Gambit.

The advantage a player who is making threats has over his opponent who must respond to them. The attacking player is said to "have the initiative" and can often dictate the turn of play. The initiative often results from an advantage in time or space. The notion of the initiative was used by Steinitz (e.g. The Sixth American Chess Congress) and by Capablanca in his Chess Fundamentals (Chapter 4).

insufficient material

An endgame scenario in which all pawns have been captured, and one side has only its king remaining while the other has only its king, a king plus a knight, or a king plus a bishop. A king plus bishop versus a king plus bishop with the bishops on the same color is also a draw, since neither side can checkmate, regardless of play. Situations where checkmate is possible only if the inferior side blunders are covered by the fifty-move rule. See Draw (chess)#Draws in all games.

An external server that provides the facility to play, discuss, and view chess over the Internet.

interpose

To move a piece between an attacking piece and its target, blocking the line of attack. Interposing a piece is one of the three possible responses to a check (the others being to move the king, or capture the attacking piece).

A white bishop developed to the c4-square or a black bishop developed to c5. A bishop so developed is characteristic of the Italian Game, 1.e4 e5 2.Nf3 Nc6 3.Bc4 (particularly the Giuoco Piano, 1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5, where both players have Italian bishops), and stands in contrast to the "Spanish" bishop on b5 characteristic of the Ruy Lopez. Likewise, "Italian" may be used as an adjective denoting an opening where one or both players has an Italian bishop, such as after 1.e4 e5 2.Nf3 Nc6 3.Nc3 Nf6 4.Bc4, the Italian Four Knights Game.

[from French] "I adjust", pronounced: [ʒa.dub]. A player says "J'adoube" as the international signal that he intends to adjust the position of a piece on the board without being subject to the touched piece rule.

A pairing system where a player plays an opponent who is close in the ranking. Named after the Dutch inventor of the system, and useful when the number of participants exceeds the number of playing rounds. See also Swiss tournament and round-robin tournament.

As a spectator, making comments on a chess game that can be heard by the players. Kibitzing on a serious game while it is in progress (rather than during a post-mortem) is a serious breach of chess etiquette.

kick

Attacking a piece, typically by a pawn, so that it will move. Kicking a piece may lead to gaining a tempo, or may force the opponent to concede control of key squares.

The knight that was on the kingside at the start of the game. The terms king bishop and king rook are also used. Sometimes abbreviated "KN", "KB", and "KR" respectively.

king pawn (or king's pawn)

A pawn on the king's file, i.e. the e-file. Sometimes abbreviated "KP". Also king bishop pawn (KBP), king knight pawn (KNP), and king rook pawn (KRP) for a pawn on the f-, g-, or h-file respectively.

kingside (or king's side)

The side of the board (board-half) the kings are on at the start of the game (the e- through h-file), as opposed to the queenside. Note, the kingside is one and the same half of the board for both White and Black. It never changes during the game, also after 0-0-0 by both players the kingside remains as it was from the start. (Both kings can be located at the queenside)

This phenomenon, first described by Alexander Kotov, can occur when a player does not find a good plan after thinking long and hard on a position. The player, under time pressure, then suddenly decides to make a move, often a terrible one which was not analysed properly.

A popular chess variant in which players do not know the moves of the other and determine their moves based on limited information from a monitoring umpire. This variant of the game is sometimes referred to as blind chess, but should not be confused with blindfold chess.

Kt

The symbol sometimes used for the knight when recording chess moves in descriptive notation, mainly in older literature. An N is used instead in algebraic notation and in later descriptive notation to avoid confusion with K, the symbol for the king.

A piece vulnerable to opponent attacks because it is undefended and cannot easily be withdrawn or supported.

loose position

A position vulnerable to opponent attacks because it is overextended or its pieces are uncoordinated.

loser

Slang for a move that loses the game.

losing a tempo

See Tempo.

loss

A defeat for one of the two players, which may occur due to that player being checkmated by the other player, resigning, exceeding the time control, or being forfeited by the tournament director. Chess being a zero-sum game, this results in a win for the other player, except in the very rare circumstance where the tournament director forfeits both players, for example for cheating or both players exceeding the time control (the latter does not normally result in a double forfeit today).

The principal, most important, or most often played variation of an opening or piece of analysis. For example, 1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 0-0 6.Be2 e5 7.0-0 Nc6 8.d5 Ne7 is often referred to as the main line of the King's Indian Defence.

A bind on the light squares in the centre, particularly d5, obtained by White by placing pawns on c4 and e4. Named for Géza Maróczy, it originally referred to formations arising in some variations of the Sicilian Defence, but the name is now also applied to similar setups in the English Opening and the Queen's Indian Defence. It was once greatly feared by Black but means of countering it have been developed since the 1980s and earlier.

match

A competition between two individuals or two teams. A match may be the entire competition, or it may be a round in a knockout tournament or team tournament. Unlike in some sports where the word match is sometimes used to describe a single game, a chess match always consists of at least two games (and often many more).

All of a player's pieces and pawns on the board. The player with pieces and pawns of greater value is said to have a "material advantage". When a player gains a material advantage they are also said to be "winning material". See Chess piece relative value.

materialism

Playstyle characterised by a willingness to win material at the expense of positional considerations. Chess computers are often materialistic.

The part of a chess game that follows the opening and comes before the endgame, beginning after the pieces are developed in the opening. This is usually roughly moves 20 through 40.

miniature

A short game (usually no more than 20 to 25 moves), for example: 1.e3 e5 2.Qf3 d5 3.Nc3 e4 4.Qf4?? Bd6! and White resigned in NN–Künzel (1900, Europe)[7] because his queen is trapped. However, a significant minority of authors include games up to 30 moves.[8] Usually only decisive games (not draws) are considered miniatures. Ideally, a miniature should not be spoiled by an obvious blunder by the losing side. A miniature may also qualify as a brilliancy. The Opera game is a famous example. Sometimes called a brevity [chiefly British].

The ability of a piece, or of a player's pieces collectively, to move around the board. (In computer chess this is often measured by the number of legal moves available.) Effectively means much the same as space.

move

A full move is a turn by both players, White and Black. A turn by either White or Black is a half-move, or (in computer context) one ply.

Following Nimzowitsch's idea, a move with a rook that seems to have no threat or purpose, but which actually discourages the opponent from a certain type of action (prophylaxis), or sets up a very deep, well-concealed plan.

An abbreviation sometimes used for the chess opening reference Nunn's Chess Openings. Cf. ECO and MCO.

NN (or N.N.)

Used in a game score in place of a player whose name is not known. The origin of this usage is uncertain. It may be an abbreviation of the Latinnomina (names), it may be short for the Latin phrase nomen nescio, "name unknown" (literally "I do not know the name") or it may come from the use of "N or NN" (later read as "N or M") in the Anglican Catechism. See also Amateur.

A performance at a chess tournament that indicates a player is ready to receive a title, or the level of performance needed. In addition to other requirements, a certain number of norms is generally required to earn a title. See Grandmaster and International Master.

This refers to the stronger player giving the weaker player some sort of advantage in order to make the game more competitive. It may be an advantage in material, in extra moves, in time on the clock, or some combination of those elements. Since the advent of the chess clock, time odds have become more common than material odds. In "time odds" the stronger player may begin the game with only one or two minutes on the clock, while the weaker player may be given five or more minutes on the clock.

The beginning moves of the game, roughly the first 10–20 moves. In the opening players set up their pawn structures, develop their pieces, and typically castle. The opening precedes the middlegame.

Opening preparation

Home study and analysis of openings and defenses that one expects to play, or meet, in later tournament or match games. In high-level play, an important part of this is the search for theoretical novelties that improve upon previous play or previously published analysis.

Opening repertoire

The set of openings played by a particular player. The breadth of different players' repertoires varies from very narrow to very broad. For example, a player who always opens with 1.e4; always meets 1.e4 with the Sicilian Defence, and the Najdorf Variation of it if allowed; and always meets 1.d4, 1.c4, or 1.Nf3 with 1...f5, intending to play the Dutch Defence, has a very narrow opening repertoire. Bent Larsen, who opened at various times with 1.e4, 1.d4, 1.c4, 1.f4, 1.Nf3, 1.b3, and 1.g3, and played a large number of different defences as Black, had a very broad opening repertoire.

Opening system

An opening, such as the Colle System or Hippopotamus Defence, that is defined by one player's moves, which can be played generally regardless of the moves of the opponent.

A situation in which two kings stand on the same rank, file or diagonal with one empty square between them. The player to move may be forced to move the king to a less advantageous square. Opposition is a particularly important concept in endgames.

Both sides playing their best move at each turn, or one of equally good alternatives. One side tries to win as quickly as possible while the other side tries to delay it as long as possible, or optimal play may result in a draw.

A passed pawn that is near the edge of the board and far away from other pawns. In the endgame, such a pawn can often constitute a strong advantage for its owner as it diverts the opponent's forces in order to restrain its advance, allowing its owner free rein elsewhere on the board.

Overextended

A position where a player has moved a piece or group of pieces (usually pawns) away from the rest in such a way that they are too difficult to defend.

A piece that has too many defensive duties. An overloaded piece can sometimes be deflected, or required to abandon one of its defensive duties.

Overprotection

The strategy of protecting a pawn or specific square of the chessboard more than is immediately necessary. This serves to dissuade the opponent from attacking that specific point and provides greater freedom of movement for the pieces protecting that square. This can cause an opponent to pursue a faulty plan or no plan at all. Aron Nimzowitsch was one of the foremost proponents of overprotection.

The assignment of opponents in a tournament. Pairing is made more difficult in chess because of the need to try to give each player an equal number of games playing White and Black and to try to not assign a player the same color in too many consecutive games. The most common pairing methods used in chess tournaments are round-robin and the Swiss system.

A player's pawns in the board centre. By extension, pawns on the squares adjacent to the centre may also be considered as part of the pawn centre. Having an ample pawn centre was considered a huge advantage until the hypermodernist school nuanced this judgment. See King's Indian Defence, Four Pawns Attack for an example of an opening leading to an extended pawn centre.

Pawn chain

A locked diagonal formation of pawns, each one supported by a friendly pawn diagonally behind and blocked by an enemy pawn directly ahead. Aron Nimzowitsch considered pawn chains extensively, and recommended attacking the enemy pawn chain at its base. See pawn structure.

Pawn island

A group of pawns of one color on consecutive files with no other pawns of the same color on any adjacent files. A pawn island consisting of one pawn is called an isolated pawn.

Lichtenhein–Morphy, New York 1857

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On this diagram, Black has 3 pawn islands but White has 2. The "isolated" pawn on e5 is not isolated because it is near a file that has a white pawn.

The placement of the pawns is known as the pawn structure. As pawns are the least mobile of the pieces and the only pieces unable to move backwards, the position of the pawns greatly influences the character of the game.

A number reflecting the approximate rating level at which a player performed in a particular tournament or match. It is often calculated by adding together the player's performances in each individual game, using the opponent's rating for a draw, adding 400 points to the opponent's rating for a win, and subtracting 400 points from the opponent's rating for a loss, then dividing by the total number of games. For example, a player who beat a 2400-rated player, lost to a 2600, drew a 2500, and beat a 2300, would have a performance rating of 2550 (2800 + 2200 + 2500 + 2700, divided by four).

Usually refers to an important chess endgame which illustrates a drawing technique when the defender has a king and rook versus a king, rook, and pawn. It is also known as the third rank defence, because of the importance of the rook on the third rank cutting off the opposing king. It was analyzed by Philidor in 1777. See also Rook and pawn versus rook endgame.

One of the chessmen or figures used to play the game—king, queen, rook, bishop, knight or pawn. Each piece type has its own rules of movement on the board. The word "piece" can refer to any chess piece including pawns (as in the touched piece rule), or it can refer to a minor piece (as in "I hung a piece"), depending on context. It can also mean a major or minor piece, as in "White needs to get some pieces to the kingside."

When a piece cannot move (either legally or advisedly) because doing so would expose a valuable piece, usually the king or queen, to attack. Pins against the king are called absolute because it is then illegal to move the pinned piece. Other pins are called relative pins.

Plan

A strategy used by a chess player to make optimal use of his advantages in a specific position while minimizing the impact of his positional disadvantages.

Playable

Said of an opening or move that gives the person playing it a tenable position, for example "Petroff's Defense is playable." or (after 1.e4 e5 2.Bc4 Nf6 3.Nc3 Nxe4 4.Nxe4) "4... d5 is the only playable move", implying that there are other legal moves, but they all leave the player in a worse position.

Play by hand

an idiomatic expression meaning to make a move without analyzing the move.

This is a popular computer-processible ASCII format for recording chess games (both the moves and related data).

Positional play

Play dominated by long-term maneuvering for advantage rather than by short-term attacks and threats, and requiring judgment more than extensive calculation of variations, as distinguished from tactics.

A sacrifice in which the lost material is not regained via a combination, but instead gains positional compensation. These typically require deep positional understanding and are often overlooked by computers. Also known as a "true sacrifice", as opposed to a pseudo-sacrifice or sham sacrifice.

Post-mortem

Analysis of a game after it has concluded, typically by one or both players and sometimes with spectators (kibitzers) contributing as well.

Prepared variation

A well-analyzed novelty in the opening which is not published but first used against an opponent in competitive play.

The Professional Chess Association (PCA) was a rival organisation to FIDE, the international chess organization. The PCA was created in 1993 by Garry Kasparov and Nigel Short for the marketing and organization of their chess world championship. The PCA lost its main sponsor, Intel, in 1996 and folded soon after.

White ranks are indicated at the left (a-file); Black ranks are indicated at the right (h-file).

Rank

A row of the chessboard. In algebraic notation, ranks are numbered 1–8 starting from White's side of the board; however, players customarily refer to ranks (but not files) from their own perspectives. For example: White's king and other pieces start on his first (or "back") rank, whereas Black calls the same rank the eighth rank; White's seventh rank is Black's second; and so on. If neither perspective is given, White's view is assumed. This relative reference to ranks was formalized in the older descriptive notation.

A form of chess with reduced time limit, usually 30 minutes per player.

Refute

To demonstrate that a strategy, move, or opening is not as good as previously thought (often, that it leads to a loss), or that previously published analysis is unsound. A refutation is sometimes colloquially referred to as a bust. A refutation in the context of chess problems or endgame studies is often called a cook.

A move a player has available. Such a move may not be crucial to the position on the board, but being able to force the opponent to move by making a reserve move can on occasion result in a significant advantage.

To concede loss of the game. A resignation is usually indicated by stopping the clocks, and sometimes by offering a handshake or saying "I resign". The traditional way to resign is by tipping over one's king, but this is rarely done nowadays.[9] In master and serious amateur play, it is much more common for a game to be resigned than for it to end with checkmate, because experienced players can foresee checkmate well in advance.

This is a tournament in which each participant plays every other participant an equal number of times, for example in the Hastings 1895 chess tournament. In a double round-robin tournament the participants play each other exactly twice, once with white and once with black, for example in the Piatigorsky Cup. A round robin tournament is commonly used if the number of participants is relatively small. See also Swiss tournament.

A move or capture that voluntarily gives up material in return for an advantage such as space, development, or an attack. A sacrifice in the opening is called a gambit, especially when applied to a pawn.

The sheet of paper used to record a game in progress. During formal games, it is usual for both players to record the game using a score sheet. A completed score sheet contains the game score.

Sealed move

Lengthy OTB games can be adjourned. To prevent unfair advantage, the players can agree on the next move being secretly recorded in a sealed envelope. Upon resumption, the arbiter makes the sealed move and the game continues. See also adjournment.

Second

An assistant hired to help a player in preparation for and during a major match or tournament. The second assists in areas such as opening preparation.[10] The second assisted with adjournment analysis, before the practice of adjournments was abandoned in the 1990s.

Second player

The expression "the second player" is sometimes used to refer to Black.

An offer of material which is made at no risk, as acceptance would lead to the gain of equal or greater material or checkmate. This is in contrast to a true sacrifice in which the compensation is less tangible. Also called a pseudo-sacrifice.

Sharp

Risky, double-edged, highly tactical. Sharp can be used to describe moves, maneuvers, positions, and styles of play.

Shot

Slang for an unexpected or sharp move that typically makes a tactical threat or technical challenge for the opponent.

Simplification

A strategy of exchanging pieces of equal value. Simplification can be used defensively to reduce the size of an attacking force. It can also be used by a player with an advantage to amplify that advantage or reduce the opponent's counterplay. Simplification is also used as an attempt to obtain a draw, or as an attempt to gain an advantage by players who are strong in endgame play with simplified positions. Also liquidation and trading.

A checkmate delivered by a knight in which the mated king is unable to move owing to it being surrounded (or smothered) by its own pieces. This could occur, for example, after 1.e4 Nc6 2.Ne2 Ne5, and now either 3.c3?? Nd3# or 3.g3?? Nf3#. Smothered mate is often achieved by sacrificing the queen.

In the tournament played by Sofia rules, players are not allowed to draw by agreement. They could have draws by stalemate, threefold repetition, fifty-move rule, or insufficient material. Other draws are allowed only if the arbiter declares the game reached a drawn position.

Solid

An adjective used to describe a move, opening, or manner of play that is characterized by minimal risk-taking and emphasis on quiet positional play rather than wild tactics.

Evaluation of game positions and setting up goals and longer-term plans for future play, as opposed to a tactic which is a shorter-term plan typically consisting of a well-defined sequence of moves and their contingent moves from a given game position.

Strength (or Strong)

A forceful or good move, a position having good winning chances, a highly rated player or one successful in tournaments, or a tournament having a sizable number of strong players competing, such as grandmasters. A "strong showing" refers to a player's high win ratio in a tournament. Opposite of weakness /weak, for example, a weak square.

Strongpoint

1. A "strongpoint defense" means an opening which defends and retains a central pawn (White: e4 or d4; Black: e5 or d5), as opposed to exchanging the pawn and relinquishing occupation of that central square.

2. More generically, a strongpoint can be any square heavily defended.

Sudden death

The most straightforward time control for a chess game: each player has a fixed amount of time available to make all moves. See also Fast chess.

This is a tournament that uses the Swiss system to determine player pairings. The basic idea is that every round each player is paired with an opponent with the same (or close to the same) score. The 33rd Chess Olympiad is an example of a Swiss tournament. See also round-robin tournament.

Symmetry

A symmetrical position on the chessboard means the positions of one's pieces are exactly mirrored by the opponent's pieces. This most often occurs when Black mimics White's opening moves. Black is said to break symmetry when he makes a move no longer imitating White's move.

1. A position for the pieces from which a shatranj game was started: piece movement in shatranj was slow, hence games were possibly started from standard position, named Tabiyas, obtained by standard move sequences from the initial position.

2. As extension: the final position of a well-known chess opening. The position (e.g. the isolani) can be reached via different move sequences, even arising from different openings, and is usually considered prototypical in terms of strategic ideas.

3. (from 2) The opening position from which two players familiar with each others' tastes begin play.

An extra move, an initiative at development. A player gains a tempo (usually in the opening) by making the opponent move the same piece twice or defend an enemy piece. In the endgame, one may wish to lose a tempo by triangulation to gain the opposition. (Plural: tempos or tempi.)

Text move

This term is used in written analysis of chess games to refer to a move that has been played in the game as opposed to other possible moves. Text moves are usually in bold whereas analysis moves are not.

Theme tournament

A chess tournament in which every game must begin with a particular chess opening specified by the organizers, for example the Budapest Gambit (1.d4 Nf6 2.c4 e5).

A draw may be claimed if the same position occurs three times with the same player to move, and with each player having the same set of legal moves each time (the latter includes the right to take en passant and the right to castle).

This refers to a number of different systems that are used to break ties, and thus designate a single winner, where multiple players or teams tie for the same place in a Swiss system chess tournament.

Time

Opportunities to make moves: similar meaning to tempo. A move that does not alter the position significantly is described as "wasting time", and forcing the other player to waste time is described as "gaining time".

The allowed time to finish a game, usually measured by a chess clock. A time control can require either a certain number of moves be made per time period (e.g., 40 moves in 2½ hours) or it can limit the length of the entire game (e.g., 5 minutes per game for blitz). Hybrid schemes are used, and time delay controls have become popular since the widespread use of digital clocks.

In team chess, the player who is assigned to face the strongest opponents. Also called first board. Second board faces the next strongest players, followed by third board, and so on. Generally board assignments must be made before the competition begins and players may not switch boards, although reserve players are often allowed as substitutes.

The rule requiring a player who touches a piece that has at least one legal move to move that piece (and, if the player moves the piece to a particular square and takes his hand off it, to move it to that square). Castling must be initiated by moving the king first, so a player who touches his rook may be required to move it, without castling. The rule also requires a player who touches an opponent's piece to capture it if possible. A player wishing to touch a piece to adjust its position on a square without being required to move it signals this intent by saying "J'adoube" or "I adjust". This way of playing is common in official games, in favour of clock move.

A competition involving more than two players or teams, generally played at a single venue (or series of venues) in a relatively short period of time. A tournament is divided into rounds, with each round consisting either of individual games or matches in the case of knockout tournaments and team tournaments. The assignment of opponents is called pairing, with the most popular systems being round-robin and Swiss. Tournaments are usually referred to by combining the city in which they were played with the year, as in "London 1851", although there are well-known exceptions, such as "AVRO 1938".

Tournament book

A book recording the scores of all the games in a tournament, usually with analysis of the best or most important games and some background on the event and its participants. One well-known example is Bronstein'sZurich International Chess Tournament 1953. The less comprehensive tournament bulletin is usually issued between the rounds of a prestigious event, giving the players and world media an instant record of the games of the previous round. Individual copies may be bundled together at the conclusion of the event to provide an inexpensive alternative to the tournament book.

Tournament director (TD)

Organizer and arbiter of a tournament, responsible for enforcing the tournament rules and the Laws of Chess. Also tournament controller [chiefly British].

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With 4...Nbd7 Black sets a trap in the QGD (1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.Bg5). White cannot win the d5-pawn due to the Elephant Trap.

Promoting a pawn to a rook, bishop, or knight instead of a queen. Rarely seen unless the knight can deliver a crucial check, or when promotion to a rook or a bishop instead of a queen is necessary to avoid stalemate.

A square that cannot be easily defended from attack by an opponent. Often a weak square is unable to be defended by pawns (a hole) and can be theoretically occupied by a piece. Exchange or loss of a bishop may make all squares of that bishop's color weak resulting in a "weak square complex" on the light squares or the dark squares.

1. The designation for the player who moves first, even though the corresponding pieces, referred to as "the white pieces", are sometimes actually some other (usually light) color. See also Black and first-move advantage.

2. Similarly, the light-colored squares on the chessboard are often referred to as "the white squares" even though they often are not literally white.

A combination in which two pieces work together to deliver an alternating series of checks and discovered checks in such a way that the opposing king is required to move on each turn. It is a potent technique since on every other move, the discovered check may allow the non-checking piece to capture an enemy piece without losing a tempo. The most famous example is Torre–Lasker, Moscow 1925. Also called a seesaw.

Wing

The queenside a-, b-, and c-file, or the kingside f-, g-, and h-file. Also called flank.

The name given to variations of several openings in which one player gambits a wing pawn, usually the b-pawn.

Winning percentage

A number calculated by taking the percentage of games won by a player plus half the percentage of drawn games. Thus, if out of 100 games a player wins 40, draws 32, and loses 28, her winning percentage is 40 plus half of 32, i.e. 56 percent.

Winning position

A position is said to be a winning if one specified side, with correct play, can eventually force a checkmate against any defence (i.e. perfect defence). Also called a won game.

[German] An "in-between" move played before the expected reply. In general, this involves responding to a threat by posing an even bigger threat to the opponent, forcing him to respond to the threat first.